The different contributions to the partial heat capacity of proteins in aqueous solution have been recently identified and quantified. The first term depends only on the covalently bonded structure of the protein and predominantly contains contributions from vibrational frequencies arising from stretching and binding modes of each covalent bond as well as internal rotations. For a typical globular protein in solution the vibrations and internal rotations of the covalent structure of the protein are responsible for the bulk of its heat capacity. A second term accounts for the non-covalent interactions within the protein molecule itself without including intermolecular interactions. The contribution of these non-bonded interactions to the partial heat capacity of a protein is very small and in the order of 3 to 5%. Finally, the hydration term, accounts for about 15% of the partial heat capacity of the protein in aqueous solution. Though the heat capacity of a dehydrated protein represents the bulk of the heat capacity of the protein in solution, very little is known about its temperature dependence, change with amino acid composition or conformational state of the protein. Another important issue that needs to be explored is how the partial heat capacity of a protein changes with its degree of hydration (from completely anhydrous to infinite dilution). In order to address some of these questions we have decided to study the heat capacity of several small globular proteins in their anhydrous state. The removal of the water molecules solvating the protein enhances its thermal stability. In the anhydrous state, a typical globular protein retains its folded conformation at temperatures as high as 170 - 200 C. We have measured the heat capacity of several anhydrous protein from sub-ambient temperatures up to around 150 C without detecting any conformational change. When the sample is heated to temperatures above 200 C, an endotherm is clearly visible in the heat capacity vs. temperature profile indicating that the protein has undergone a conformational change. Upon cooling the sample, neither the endotherm nor the activity of the protein is recovered, indicating that this heat-induced denaturation of the protein has induced irreversible changes which preclude the protein from returning to its native (biologically active) conformation.